Hitherto, research relating to a graphical user interface (GUI) has been conducted with the objective of enabling a user to intuitively operate an information processing apparatus such as a personal computer (PC). Typically, with a GUI, by using a pointing device, for example, to move a pointer on a display screen and by selecting an object such as an icon or a button on the display screen, the user can make a computer execute a process corresponding to the selected object.
Furthermore, a technology for the user to operate a display screen without using input devices such as a keyboard, a mouse, and the like has been proposed. For example, Patent Literature 1 discloses a technology that determines details of an operation performed on a display screen by an operator by recognizing a gesture operation performed with both hands of the operator.